1. Field of the Invention
The present invention relates to an electrical connector assembly for electrically connecting an electronic package such as a central processing unit (CPU) with a circuit substrate such as a printed circuit board (PCB), and particularly to a land grid array (LGA) connector assembly having a base and a frame readily joined together.
2. Description of the Prior Art
Electrical connector assemblies are widely used for electrically connecting land grid array (LGA) central processing units (CPUs) with printed circuit boards (PCBs). This kind of connector assembly is described in xe2x80x9cNonlinear Analysis Helps Design LGA Connectorsxe2x80x9d, which is obtained from the web journal xe2x80x9cConnector Specifierxe2x80x9d (February, 2001). A similar electrical connector assembly is disclosed in U.S. Pat. No. 5,344,334.
Generally, each such conventional electrical connector assembly is mounted on a PCB that defines four bores. The electrical connector assembly comprises a base receiving a plurality of electrical contacts therein, and a frame assembled on the base. The frame defines an opening in a middle thereof, and four screw holes at respective corners thereof. The base defines a plurality of passageways receiving the contacts therein, and four holes corresponding to the screw holes of the frame. In assembly, the base is attached on the PCB, with the holes of the base above the corresponding bores of the PCB. The frame is attached on the base, with the screw holes above the corresponding holes of the base. Four bolts are extended through respective bores of the PCB and respective holes of the base to engage in respective screw holes of the frame, thereby assembling the electrical connector assembly with the PCB.
However, it takes an unduly long time to screw the bolts when assembling the electrical connector assembly with the PCB. This retards the efficiency of assembly, which is particularly significant in mass production facilities. In addition, the base and the frame are at all times separate parts prior to their assembly on the PCB. This increases the difficulty of transporting and handling the base and the frame.
In view of the above, a new LGA connector assembly that overcomes the above-mentioned disadvantages is desired.
Accordingly, a main object of the present invention is to provide an electrical connector assembly for electrically connecting a CPU and a PCB, wherein the connector assembly can be readily assembled on the PCB.
Another object of the present invention is to provide an electrical connector assembly having a base and a frame that can be assembled together prior to mounting of the electrical connector assembly on a PCB.
To achieve the above-mentioned objects, an electrical connector assembly in accordance with a preferred embodiment of the present invention is mounted on a PCB that defines two bores diagonally opposite from each other. The electrical connector assembly comprises a base, a plurality of electrical contacts received in the base, and a frame assembled on the base. The frame defines an opening in a middle thereof, two fixing holes at diagonally opposite corners thereof, and two semi-circular orientation holes at two opposite sides thereof. The fixing hole is surrounded by a circumferential step thereat. The frame includes a planar portion having a top surface and a bottom surface. A pair of orientation projection extends perpendicularly from the top surface of the planar portion, for interferentially engaging in the orientation holes of the frame. A pair of fixing posts extends perpendicularly from the top surface of the planar portion, for snappingly engaging in the fixing holes of the frame to firmly mount the frame on the base. A pair of protrusions is located below respective orientation projections, with the protrusions depending from the bottom surface of planar portion. The protrusions interferentially engage in the bores of the PCB to firmly mount the electrical connector assembly on the PCB.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: